The present invention relates to a three-terminal double heterojunction injection laser, and more particularly to a semiconductor laser integral with a bipolar mode static induction transistor having high control efficiency.
Semiconductor lasers are small in size, produce a laser beam with high efficiency and are capable of direct modulation, and so have potential use as light sources for optical communications, optical information processing systems and optical ICs. Conventional double heterojunction injection lasers require a only small threshold current density and use a stripe geometry structure to stabilize the lasing mode. But each of them is electrically a diode and requires an external transistor for effecting direct modulation. If the stripe width is made very small, the threshold current density is extremely increased and laser oscillation is effected in many axial modes rather than in a single mode. The size of the semiconductor laser is critical in optical ICs and a reduction in the stripe width is unavoidable.